猪粪颗粒粒度、粒形的量化表征方法研究

Quantitative Characterization of Particle Size and Shape of Pig Manure

以猪粪物料为研究对象,基于去离子水分散、热风干燥-机械振荡、真空冷冻干燥-机械振荡3种分散预处理方法,分别采用激光粒度分析、扫描电镜分析、动态图像分析法测定其粒度分布和特征参数。扫描电镜观察结果表明,猪粪颗粒属于不规则颗粒;热风干燥-机械振荡分散后的样品存在较多团聚体。不同分散预处理的测定结果显示,因猪粪样品部分组分的可溶性和热风干燥-机械振荡过程中的团聚现象,宜优选真空冷冻干燥-机械振荡作为分散预处理方法。3种测量方法所获参数存在差异,其中,动态图像分析法由于采用直接测量原理和动态检测过程,可优选其作为检测畜禽粪便物料粒度分布的方法。基于真空冷冻干燥-机械振荡分散预处理和动态图像分析法,获取猪粪颗粒的纵横比和球形度分别为0.57±0.01和0.61±0.01,中值粒径为(501±16)μm,粒度分布宽度参数为1.45±0.04。

Quantitative characterization of particle morphology of manure is one of the key factors for modeling the fluid flow and degradation mechanism during manure management. This study applied three dispersion pretreatments （water dispersion, oven drying- mechanical vibration and vacuum freeze drying - mechanical vibration） and three analysis methods （scanning electron microscopy, dynamic image analysis and laser particle size analysis） to explore the particle size distribution and microscopic properties of pig manure. Scanning electron micrographs showed that manure particles had an irregular shape; the oven dried-mechanically vibrated sample had more aggregates. The comparison between the results of different pretreatments indicated that the vacuum freeze drying - mechanical vibration could be selected as the preferred method because of the soluble components of manure and the aggregates generated during the oven drying process. There were differences in the values of characteristic parameters obtained by three analysis methods, and the dynamic image analysis was suggested as an effective method because of the direct measurement of particle morphology and the high degree of automation. Based on the optimized methods, the median diameter of manure particles was （501±16）μm, the span of particle size distribution was 1.45 ±0. 04, and the shape factors including the aspect ratio and sphericity were 0. 57±0.01 and 0.61±0.01, respectively.